Glasair Gear Door Gaps

Submitted by Neal Garvin

Glasair III gear doors.

If your wing is still in the wing jig (and upside down) then the best way is to build the doors out to meet the wing surface:


Sand the primer off the perimeter of the doors for about an inch wide, both sides. Put package tape on the wing surface, retract the gear, put a little mill- fiber mix or q-cell around the door gap to fill the void and provide a smooth surface for the layups to sit on.

Then put a couple laminates over the edge of the doors onto the taped wing surface, staggering them on the surface of the door 1/4″ to make feathering in easier. When it cures, pop the gear door off, grind off the excess around the perimeter and then add a layer or two on the inside of the door and blend it 

Might consider making the “new” edge of the doors a little thicker since they can take some abuse from ground FOD.

You could do this if your airplane is on jack stands, but it would require working upside down for a bit which isn’t that bad.

Remember, with the wing upside down and any slop in the gear linkage, the gear will retract further due to gravity pulling it down. In flight, the air loads tend to try and suck the gear out. make sure there is adjustment remaining on the hydraulic cylinder rod-ends and between tire and upper wing skin so you can adjust the gear up tight to the wing when you are all done.

Any gap seal you glue on will be a nuisance in the long run.

One other way – if there is tire and disk clearance – is to grind away the glass on the inside of the door surface where it mounts against the half fork to move the door closer to the wheel. You would have to re-glass the surfaces so be sure to account for the layups when fitting the door this way.

A consideration: Our half fork door inner surfaces are about 1/4″ from the surface of the brake disk on the aft side and the paint is all blistered and burnt off the inside surface of the door from the disk heat. And we are even conservative and gentle on the brakes using as much aerodynamic braking as possible.

We also had to relieve the inside aft surface of the door for tire clearance. Even though there was 1/2″ clearance between the tire and door (at about the 8-o’clock position looking at the right door from the wing tip side), it wasn’t enough. The tire’s flat spot on the bottom (thus wider) doesn’t rebound quickly enough at landing/take-off speed and it rubs the paint off the inside of the door. Was really bad when the tire pressure was low.

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